Spent fuel rod splitting due to UO2 oxidation during dry storage: Assessment of the database

Consequence Analysis of Residual Water in a Storage Canister (Preliminary Report)

“…Gross rupture of a cladding is defined when crack width exceeds 1 mm (NRC, 2007). Kohli, et al (1985) reported that the initial crack size of the damaged LWR fuel ranged from 0.4 to 7 cm with average length of 3.5 cm. After 2,100 hours' exposure in the air at 325 °C, the crack propagated up to about 10 cm in the axial direction.…”

“…The incubation time increased from about 10 hours to 100 hours for 16 and 42 GW-day/MTU, respectively. Hanson (1998) suggested possible retardation effect of substitutional cations, such as uranium to plutonium, and fission products delay or hinder U 3 O 8 formation Herranz and Feria (2009). presented a similar dependence of the incubation time on the burnup for CANDU and LWR fuels (8 to 27 GWday/MTU).…”

Hydride Reorientation and Delayed Hydride Cracking of Spent Fuel Rods in Dry Storage

“…In other words, although a pin hole crack or a hairline crack is formed, this fine crack will not grow by DHC due to the disappearance of hoop stresses, maintaining the gross integrity of the spent fuel rods. However, this assumption is too simple due to the ignorance of the stresses induced by fuel expansion [32] caused by UO 2 oxidation in dry storage. Fortunately, a good number of studies [32][33][34][35] were conducted on the behavior of failed fuel rods in oxidizing atmospheres, demonstrating that propagation of the defect has occurred when cladding deformation due to fuel oxidation in air exceeds a critical level.…”

“…However, this assumption is too simple due to the ignorance of the stresses induced by fuel expansion [32] caused by UO 2 oxidation in dry storage. Fortunately, a good number of studies [32][33][34][35] were conducted on the behavior of failed fuel rods in oxidizing atmospheres, demonstrating that propagation of the defect has occurred when cladding deformation due to fuel oxidation in air exceeds a critical level. However, Nakamura et al [35] reported that the critical level for crack propagation was inconsistently unpredictable depending on the experimental conditions, for which no clear explanations were given.…”

Effect of applied current on the formation of defect in PWR nuclear fuel rods in resistance pressure welding process

“…The nuclear fuel rod consists of UO 2 pellets, a ZIRLO tube, top and bottom end plugs, plenum spring, helium gas, etc., and depending on the design, axial blanket pellets are also components of the nuclear fuel rod. Basically, the cladding materials of these nuclear fuel rods containing UO 2 pellets should not be damaged during power plant operation [6]. Moreover, the nuclear fuel rods act as a pressure vessel that prevents the leakage of radioactive fission products [7,8].…”